USA: Redondo Beach Replenishment Begins
Since April, a massive clamshell dredge floating off the marina has collected sand and loaded it onto barges bound for the port of Long Beach, which needs the material for a harbor redevelopment project.
Starting Thursday, the U.S. Army Corps of Engineers’ multimillion-dollar dredging operation will shift gears. Sediment unearthed by the 2,095-ton Paula Lee dredge will either be dropped off the coast of Redondo Beach or pumped onto a swath of sand south of the pier.
The project, which will last about 40 days, calls first for depositing roughly 85,000 cubic yards of marina sediment into water depths of 30-50 feet near the Topaz Street jetty.
Residents and beachgoers can expect to see a large, flat-bottom vessel called a scow transporting wet sand to thearea, county beaches and harbors officials said. It will make drops twice a day near the jetty, each taking about 30 minutes to complete.
“That’s a natural depression that will store the material for future replenishment projects,” said Cesar Espinosa of the Department of Beaches and Harbors, the dredging project’s sponsor.
The focus then will shift to a section of narrowed beach between the Topaz jetty and Ruby Street, he said. There, about 75,000 cubic yards of sediment will be pumped onto the sand from a barge anchored 1,000 feet off the coastline. The sand will travel through an underwater plastic pipe at a daily rate of 2,000 cubic yards – or the equivalent of 200 daily dump truck loads, county officials said.
Bulldozers will spread the sand across the beach, and workers will shift the pipe opening periodically to ensure the material is evenly distributed. The sediment will come from the north entrance to the marina channel and meets the approval of regulatory agencies for onshore beach nourishment, county officials said. (The material reserved for Long Beach came from the south channel entrance, and is said to be more contaminated given its proximity to Ballona Creek.)
Given that the barge will face a row of high-rise condominiums lining Redondo Beach’s Esplanade, and that loaloads of wet sand will land on a fairly busy section of beach, city and county officials are eager to get the word out.
Redondo Beach has been preparing for the project for some time and mailed letters to roughly 150 nearby residents alerting them of the planned activity, said Steve Huang, the city engineer and chief building official. This week the beach town will send out a reminder, warning people that lights may be visible at night (county officials say they will face down, however) and that the new beach sand could have an odor, he said.
“When you first pump the sand through the water (and) onto the beach it’s black in color and a little bit smelly … fishy,” Huang said. “Different people have different perceptions of it.”
But that’s not for long, he added. The hot sun eventually will dry out and bleach the dredged sand.
The last time sediment was removed from both the marina’s north and south channel entrances was in 1999.
Around that time, the beach near Topaz Street measured up to 180 feet from the water’s edge to the bike path, Espinosa said. Today, he said it’s about half that size – and in some places the shoreline is less than 60 feet wide.
When the project is finished, the width of the beach in some places will measure 100 feet but the area near Ruby Street will remain more narrow. However, county officials said the sand placed near Topaz will naturally pull north to help maintain the narrower areas of the beach.
Before the dredging plan started, officials had complained the entrance to the marina had become so clogged that commercial boaters, pleasure craft and vessels operated by county sheriff’s deputies and lifeguards had difficulty navigating it, especially during low tide when the water level in the north channel entry dropped to just a couple feet.
The $13 million project, funded with federal money and $5.3 million from the county’s portion of motor vehicle license fees, is designed to create a 20-foot depth at the harbor entrance during low tide.
Long Beach and Redondo Beach aren’t the only areas making use of the marina’s dredge material. Just a few weeks ago, Espinosa said, about 140,000 cubic yards of clean sediment was deposited near shore at Dockweiler Beach for another replenishment project.
Press Release, August 16, 2012